retool image cache to be generic cache

src/core/SkBitmapProcState.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapCache.h"
 #include "SkBitmapProcState.h"
 #include "SkColorPriv.h"
@@ skipping 91 matching lines @@
     v1.fY = mat.getSkewY();
 
     v2.fX = mat.getSkewX();
     v2.fY = mat.getScaleY();
 
     return SkMaxScalar(v1.lengthSqd(), v2.lengthSqd());
 }
 
 class AutoScaledCacheUnlocker {
 public:
-    AutoScaledCacheUnlocker(SkScaledImageCache::ID** idPtr) : fIDPtr(idPtr) {}
+    AutoScaledCacheUnlocker(SkScaledImageCache::ID* idPtr) : fIDPtr(idPtr) {}
     ~AutoScaledCacheUnlocker() {
         if (fIDPtr && *fIDPtr) {
             SkScaledImageCache::Unlock(*fIDPtr);
             *fIDPtr = NULL;
         }
     }
 
     // forgets the ID, so it won't call Unlock
     void release() {
         fIDPtr = NULL;
     }
 
 private:
-    SkScaledImageCache::ID** fIDPtr;
+    SkScaledImageCache::ID* fIDPtr;
 };
 #define AutoScaledCacheUnlocker(...) SK_REQUIRE_LOCAL_VAR(AutoScaledCacheUnlocker)
 
 // Check to see that the size of the bitmap that would be produced by
 // scaling by the given inverted matrix is less than the maximum allowed.
 static inline bool cache_size_okay(const SkBitmap& bm, const SkMatrix& invMat) {
     size_t maximumAllocation
         = SkScaledImageCache::GetSingleAllocationByteLimit();
     if (0 == maximumAllocation) {
         return true;
@@ skipping 928 matching lines @@
     } else {
         size >>= 2;
     }
 
     if (fFilterLevel != SkPaint::kNone_FilterLevel) {
         size >>= 1;
     }
 
     return size;
 }